on the environment is considering a proposal to ban butterfly releases in the city. >> the commercial release of butterflies really offsets some of the scientific research that folks are doing to try to monitor and to keep an effective count on what the native specious looks like. >> reporter: monarch papers say they don't breed, they are sterile and provide no threat to the government. doesn't the city council have bigger fish to fry? >> this is a democracy. this was brought to your attention. >> would you do this with squirrels or bats? >> reporter: that's a good question. in san francisco, donford, kpix5. >>> a recent report says the monarch butterfly population had low migration levels from mexico. >>> the first day of what is a cold snap. the cold temps will be felt across the bay area. >> you forgot, you were quickly reminded when you went outside. >> today was the one day to forget. starting tomorrow, bring your scarf, your jacket, and the kids need a thicker jacket going to school. maybe you will just sit in inside all day to watch channel 5. i want to show you what is going on first.